l = [1,2,3]
# 反转
# print(l[::-1])
# l.reverse()
# print(l)

# 去重
l1 = [1,2,3,4,5,6,6,7]
# print(list(set(l1)))

# l2 = []
# for i in l1:
#     if i not in l2:
#         l2.append(i)
# print(l2)

# d = {} # 字典的Key不能重复
# for i in l1:
#     d[i] = i
# print(list(d.keys()))